Combustion chemical vapor deposition (combustion CVD) is a relatively new technique for the growth of coatings. Combustion CVD is described, for example, in U.S. Pat. Nos. 5,652,021; 5,858,465; and 6,013,318, each of which is hereby incorporated herein by reference in its entirety.
Conventionally, in combustion CVD, precursors are dissolved in a flammable solvent and the solution is delivered to the burner where it is ignited to give a flame. Such precursors may be vapor or liquid and fed to a self-sustaining flame or used as the fuel source. A substrate is then passed under the flame to deposit a coating.
There are several advantages of combustion CVD over traditional pyrolytic deposition techniques (such as CVD, spray and sol-gel, etc.). One advantage is that the energy required for the deposition is provided by the flame. Another advantage is that combustion CVD techniques do not necessarily require volatile precursors. If a solution of the precursor can be atomized/nebulized sufficiently, the atomized solution will behave essentially as a gas and can be transferred to the flame without requiring an appreciable vapor pressure from the precursor of interest. An atomized solution generally contains particle sizes small enough that the droplets do not experience inertial separation from the gas and impact the conduit (e.g., via inertial impaction) but large enough so that the solution does not separate from the gas diffusionally (e.g., via diffusional impaction).
In the areas of chemical vapor deposition (CVD) and bulk materials synthesis from molecular precursors, it has been shown that the molecular structure and composition of the precursor may enable the kinetic isolation of meta-stable phases and generate unique forms of target solid-state material (for a review, see Paul O'Brien and Ryôki Nomura, “Single-molecule precursor chemistry for the deposition of chalcogenide (S or Se)-containing compound semiconductors by MOCVD and related methods,” J Mater. Chem., vol. 5, no. 11, pp. 1761-1773 (1995)). One of the more interesting examples in the literature is given by Barron and co-workers in the deposition of cubic GaS from the novel cubane molecular precursor [(tBu)GaS]4 (Andrew N. MacInnes et al., “Chemical vapor deposition of cubic gallium sulfide thin films: a new metastable phase,” Chem. Mater., vol. 4, no. 1, pp. 11-14 (1992); Andrew N. MacInnes et al., “Chemical vapor deposition of gallium sulfide: phase control by molecular design,” Chem. Mater., vol. 5, no. 9, pp. 1344-1351 (1993)).
Thus, it will be appreciated that there is evidence that the precursor can influence the phase, microstructure, and/or other properties of the deposited material. To this end, it will be appreciated that combustion deposition techniques may be used to deposit metal oxide coatings (e.g., singly-layer anti-reflective coatings) on glass substrates, for example, to alter the optical properties of the glass substrates (e.g., to increase visible transmission).
For example, in certain example embodiments, combustion deposition may be used to deposit coatings of silicon oxide (e.g., SiO2 or other suitable stoichiometry) using silicon precursors. As will be described in greater detail below, it has been determined that the coatings produced using the techniques disclosed herein have improved transmission-enhancing and/or reflection-reducing properties as compared to conventional CVD or combustion deposited coatings grown from typical silicon precursors such as, for example, hexamethyldisiloxane (HMDSO), tetraethyl orthosilicate (TEOS), silicon tetrachloride (SiCl4 or other suitable stoichiometry), trialkyl silanes (R3SiH or other suitable stoichiometry), and alkoxy silanes (R2Si(OR′)2, where R is H or an organic group and R′ is an organic group). U.S. Publication No. 2006/0003108, the entire contents of which are hereby incorporated herein by reference, discloses prior art techniques for using flame deposition to deposit SLAR coatings).
It also will be appreciated that there is a need in the art for combustion deposition techniques that represent an improvement over conventional combustion CVD techniques, and/or improved techniques for depositing metal oxide coatings (e.g., single layer anti-reflective coatings) on glass substrates via combustion deposition.
In certain example embodiments of this invention, a method of forming a coating on a glass substrate using combustion deposition is provided. A glass substrate having at least one surface to be coated is provided. An organosiloxane inclusive precursor at least initially having a ring- and/or cage-like structure to be combusted is introduced. Using at least one flame, at least a portion of the precursor is combusted to form a combusted material, with the combusted material comprising non-vaporized material. The glass substrate is provided in an area so that the glass substrate is heated sufficiently to allow the combusted material to form the coating, directly or indirectly, on the glass substrate.
In certain example embodiments, a method of forming a coating on a glass substrate using combustion deposition is provided. A glass substrate having at least one surface to be coated is provided. An organosiloxane inclusive precursor at least initially having a ring- and/or cage-like structure to be combusted is introduced. Using at least one flame, at least a portion of the precursor is combusted to form a combusted material, with the combusted material comprising non-vaporized material. The glass substrate is provided in an area so that the glass substrate is heated sufficiently to allow the combusted material to form the coating, directly or indirectly, on the glass substrate. The deposited coating comprises silicon oxide. The coating increases visible transmission of the glass substrate by at least about 2.0%.
Thus, the organosiloxane inclusive precursor having a ring- and/or cage-like structure may affect the phase, microstructure, and/or other properties of the deposited material in certain example embodiments. This may advantageously result in, for example, transmission-enhancing and/or reflection-reducing properties in certain example implementations.
The features, aspects, advantages, and example embodiments described herein may be combined to realize yet further embodiments.